1. Technical Field
The present disclosure relates to a light guide plate for use in a backlight module.
2. Description of Related Art
In a typical liquid crystal display device, a liquid crystal panel of the liquid crystal display device relies on a backlight module powered by electricity to supply the light needed to display images and data.
Currently, backlight modules can be classified as either an edge lighting type or a bottom lighting type depending upon the location of lamps within the device. A typical edge lighting type backlight module includes a light source and a light guide plate. The light guide plate includes a light input surface located at a side surface thereof, a light output surface adjoining the light input surface, and a reflecting surface positioned opposite the light output surface. The light source is generally positioned at the light input surface of the light guide plate. The light guide plate may have a plurality of light scattering microstructures positioned on the reflecting surface. The plurality of scattering microstructures can sufficiently scatter light, thereby improving the optical uniformity of the backlight module.
However, the plurality of scattering microstructures is generally printed or chemically etched on the reflecting surface. As a result, each of the scattering microstructures has a large size because of a low machining precision of the printing or chemical etching, and each of the scattering microstructures is generally brighter than an area around the scattering microstructure. Thus, light spots of the scattering microstructures often occur.
In order to reduce or eliminate the light spots of the scattering microstructures, the backlight module further includes a light diffusion film positioned on top of the light guide plate, and prism sheets positioned on top of the light diffusion film. Light emitted from the light guide plate is scattered by the light diffusion film, condensed by the prism sheets, and emitted from the backlight module. However, an air gap exists at the boundary between the light diffusion film and the light guide plate. When the backlight module is in use, instead of all of the light emitted from the light guide plate passing through the air gap, some of the light undergoes total reflection at one or both of the corresponding boundaries. In addition, the light diffusion film may absorb some of the light emitted from the light guide plate. As a result, the brightness of the backlight module is decreased.
What is needed, therefore, is a new light guide plate and a backlight module that overcome the above-mentioned disadvantages.